While booting from CD to Backtrack 5 it scrolls a load of text and then the screen messes up. I made a video.
Can anyone help? Now I can't go back to Win 7 because it's messed up the boot menu and I can't find the disk
If you were just booting the LiveCD, which it looks as though you were doing, it shouldn't have touched the boot menu. I couldn't see the top menu choice on the Backtrack 5 menu, but the top choice is rarely the install option. If by some chance it was the install option, you'll need the Windows 7 disk to do a rescue.
The text you saw scrolling on the screen was just the normal Linux boot scroll, showing you what was being set up while it was booting. LiveCD's don't touch the hard disk while they are booting. If there was anything to give me a clue in that boot scroll, I couldn't tell, because the video was so bad. Sorry.
Edit: I know some of the forum members have booted BackTrack before. If you see this, can you confirm that this looks like a normal BackTrack LiveCD boot?
One more thing, I hope this was downloaded from a secure source. If it came from anywhere other than the Backtrack home page, there may be other things going on.